VERTEBRATA. 
333 
being united by a short web, and terminating in blunt 
claws. The legs are usually feathered to the heel, some¬ 
times (as in Grouse) 
to the toes. The 
feathers of the body 
are large and coarse. 
The males generally 
have gay plumage, 
and some appendage 
to the head. The 
nostrils are covered 
by a scale or valve. 
Their main food is Eiu. 315.—Prairie-chicken {Cupidonia cupido). 
. 01 Western prairies. 
grain. Such are the 
Grouse, Partridges, Turkeys, Pheasants, Poultry, and Cu- 
rassows. 
C. Aerial Birds.— This highest and largest group in¬ 
cludes all those Birds whose 
toes are fitted for grasping 
or perching, the hind toe 
being on a level with the 
rest. The knee is free from 
the body, and the leg is 
generally feathered to the 
heel. The wings are adapt¬ 
ed for rapid or long flight; 
and they hop, rather than 
walk, on the ground. 170 
They always live in pairs; 
and the young are hatched 
helpless. 
7. Columbce , or Pigeons 
and Doves, stand intermediate between the terrestrial and 
perching Birds, as the Flamingoes, and link the aquatic 
and terrestrial. They differ from the typical Rasores in 
Fig. 316.— Ring-dove (Columba palumbus). 
England. 
